lp-441 Rev. 004 Rel. 000 Date 7.2.21
33
B. Gas Piping Requirements
1. The gas connection fitting on the water heater is 1/2” NPT.
NOTE:
The gas supply pipe size must not be less than 1/2”.
2. The supply line must be sized for the maximum output of
the water heater being installed. If there are additional
gas appliances on the main supply line, size the supply
line for the maximum total COMBINED BTU/Hr draw of the
appliances. This will ensure the supply line is sized to allow
all the appliances to operate at the same time.
3. Measure the length of the gas supply line from the gas meter
to the water heater. The water heater must be installed
downstream of the gas meter to ensure adequate gas supply.
4. Use the table in this manual or refer to the gas line
manufacturer’s sizing information to determine the correct
supply pipe size. Run the gas supply line in accordance with
all applicable codes.
5. The National Fuel Gas Code (NFPA 54) requires that a
sediment trap (drip leg) be installed in the gas line on
appliances not so equipped. The drip leg must be accessible,
a minimum of 3” in length, and not subject to freezing
conditions. See Figure 22.
6. A manual gas shut-off valve should be installed in the gas
supply line close to the water heater. Locate and install
manual shutoff valves in accordance with local and state
requirements.
7. To facilitate any future maintenance, it is also recommended
that an approved gas union fitting be installed in the supply
line between the shut-off valve and the 1/2” NPT connection
on the water heater.
8. Use a manometer to test the gas pressure to make sure it
meets the minimum standards and does not exceed the
maximum standards of the water heater.
9. Leak test the gas line pipe before placing the water heater in
operation. Only use approved leak detector liquid solutions
to check for leaks. Never use an open flame to check for leaks.
Support gas supply piping with hangers, not by the heater or its
accessories. The heater gas valve and blower will not support the
weight of the piping. Make sure the gas piping is protected from
physical damage and freezing, where required. Failure to follow
these instructions could result in gas leakage, fire, explosion,
property damage, severe personal injury, or death.
Do not use Teflon tape on gas line pipe thread. Use a pipe
compound rated for use with natural and propane gases. Apply
sparingly on male pipe ends, leaving the two end threads bare.
Failure to follow these instructions could result in gas leakage, fire,
explosion, property damage, severe personal injury, or death.
Figure 22 - Gas Connection
C. Additional Precaution for Excess Flow Valve (EFV)
If an excess flow valve (EFV) is in the gas line, check the manufacturer’s
minimum and maximum flow capacity ratings. An improperly sized
EFV will not allow for a full flow of gas to the appliance and will
cause the appliance to malfunction. See Figure 23.
Figure 23 - Excess Flow Valve (EFV)
WARNING
!
When performing a pressure test on the gas line piping, be sure
the appliance is disconnected or isolated if the test pressure is
expected to exceed 1/2 PSI (14” WC), as damage to the gas valve
could occur. Such damage could result in fire, property damage,
serious personal injury, or death.
